Visual control of action without retinal optic flow

In everyday life, the optic flow associated with the performance of complex actions, like walking through a field of obstacles and catching a ball, entails retinal flow with motion energy (first-order motion). We report the results of four complex action tasks performed in virtual environments without any retinal motion energy. Specifically, we used dynamic random-dot stereograms with single-frame lifetimes (cyclopean stimuli) such that in neither eye was there retinal motion energy or other monocular information about the actions being performed. Performance on the four tasks with the cyclopean stimuli was comparable to performance with luminance stimuli, which do provide retinal optic flow. The near equivalence of the two types of stimuli indicates that if optic flow is involved in the control of action, it is not tied to first-order retinal motion.     

Perception of heading without retinal optic flow

How do we determine where we are heading during visually controlled locomotion? Psychophysical research has shown that humans are quite good at judging their travel direction, or heading, from retinal optic flow. Here we show that retinal optic flow is sufficient, but not necessary, for determining heading. By using a purely cyclopean stimulus (random dot cinematogram), we demonstrate heading perception without retinal optic flow. We also show that heading judgments are equally accurate for the cyclopean stimulus and a conventional optic flow stimulus, when the two are matched for motion visibility. The human visual system thus demonstrates flexible, robust use of available visual cues for perceiving heading direction.     

Sources of variability in children’s language growth

The present longitudinal study examines the role of caregiver speech in language development, especially syntactic development, using 47 parent–child pairs of diverse SES background from 14 to 46 months. We assess the diversity (variety) of words and syntactic structures produced by caregivers and children. We use lagged correlations to examine language growth and its relation to caregiver speech. Results show substantial individual differences among children, and indicate that diversity of earlier caregiver speech significantly predicts corresponding diversity in later child speech. For vocabulary, earlier child speech also predicts later caregiver speech, suggesting mutual influence. However, for syntax, earlier child speech does not significantly predict later caregiver speech, suggesting a causal flow from caregiver to child. Finally, demographic factors, notably SES, are related to language growth, and are, at least partially, mediated by differences in caregiver speech, showing the pervasive influence of caregiver speech on language growth.     

Parental Influence on Children with Attention-Deficit/Hyperactivity Disorder: I. Relationships Between Parent Behaviors and Child Peer Status

We examined associations between children’s peer relationships and (a) their parents’ social competence as well as (b) their parents’ behaviors during the children’s peer interactions. Participants were families of 124 children ages 6–10 (68% male), 62 with ADHD and 62 age- and sex-matched comparison youth. Children’s peer relationships were assessed via parent and teacher report, and sociometric nominations in a lab-based playgroup. Parental characteristics were assessed via parent self-report and observations of behavior during their child’s playgroup. After statistical control of relevant covariates, parents of children with ADHD reported poorer social skills of their own, arranged fewer playdates for their children, and displayed more criticism during their child’s peer interaction than did parents of comparison youth. Parents’ socialization with other parents and facilitation of the child’s peer interactions predicted their children having good peer relationships as reported by teachers and peers, whereas parental corrective feedback to the child and praise predicted poor peer relationships. Parents’ ratings of their child’s social skills were positively associated with ratings of their own social skills, but negatively associated with criticism and facilitation of the child’s peer interactions. Relationships between parental behaviors and peer relationships were stronger for youth with ADHD than for comparison youth. The relevance of findings to interventions is discussed.     

Childhood amnesia: Empirical evidence for a two-stage phenomenon

The term childhood amnesia refers to the inability of adults to remember events from their infancy and early childhood. If we plot the number of memories that adults can recall as a function of age during childhood, the number of memories reported increases gradually as a function of age. Typically, this finding has been used to argue that gradual changes in memory development contribute to a gradual decline in childhood amnesia during the preschool period. Alternatively, it is possible that pooling data across participants has obscured more abrupt, stage-like changes in the remission of childhood amnesia. In the present study we examined the number and distribution of childhood memories for individual participants. Six adults were repeatedly interviewed about their childhood memories. We found that the distribution of adults' early childhood memories may be less continuous than pooled data suggest. This finding has important implications for current explanations of childhood amnesia.     

A Developmental Evaluation of Frequency Memory for Actions Presented in Lists,Scripts, and Stories

Although some research suggests that misinformation provided by a co-witness could be more influential than that obtained from other sources, most of this research has compared the effect of co-witness information against non-social forms of misinformation only. To better understand the influence of co-witnesses we compared the influence of co-witness misinformation with the influence of misinformation provided by an interviewer. Across two experiments using the MORI paradigm we found no evidence that a co-witness is particularly influential relative to another social source of post-event misinformation. In fact, the source of the misinformation delivered by our interviewer was less likely to be correctly recalled than the source of the misinformation delivered by a co-witness. There was some evidence that misinformation delivered by both a co-witness and an interviewer has a stronger effect on witnesses' accuracy and confidence than misinformation obtained from either source alone. Finally, our results suggest that the opportunity to provide an early individual memory account might protect against the effect of subsequently-encountered co-witness misinformation. These results have important implications for the way that criminal investigations are conducted.     

Sport-Type Differences in Alcohol Use Among Intercollegiate Athletes

Prior research has found that (a) intercollegiate athletes are especially “at-risk” for excessive alcohol consumption (e.g., Nelson & Wechsler, 2001 Nelson, T. F. and Wechsler, H. 2001. Alcohol and college athletes. Medicine and Science in Sports and Exercise, 33: 43–47. [INFOTRIEVE][CSA][CROSSREF][Crossref], [PubMed], [Web of Science ®] , [Google Scholar]), and (b) sport-type differences exist among college athletes in terms of yearly drinking prevalence rates (National Collegiate Athletic Association, 2001 National Collegiate Athletic Association. 2001. NCAA study of substance use habits of college student-athletes, Indianapolis, IN: Author.  [Google Scholar]). No studies, however, have examined sport-type differences on more specific measures of alcohol consumption (e.g., drinks per week), or examined potential mediators of the relationship between sport type and alcohol consumption. In the present study, data were analyzed on 298 intercollegiate athletes from two different universities. Resuls indicated significant sport type differences on alcohol consumption variables, with athletes from the sports of swimming and diving reporting the highest levels of alcohol consumption. Results provided partial support for the role of positively reinforcing drinking motives in mediating the sport type–alcohol consumption relationship. Findings are discussed in light of prior research in the area of college student–athlete alcohol consumption.     

The Meaning of Rorschach Inkblots,Responses and Determinants as Perceived by Children

Fifteen semantic-differential scales were applied to the Rorschach inkblots, to nine common Rorschach responses representing various Rorschach determinants, and to two determinants not embodied in responses. Ss consisted of third, sixth, and ninth grade public school children separated by sex within each group. Children significantly differentiated the inkblots on the semantic scales, with older children differentiating the blots more sharply. Girls differentiated the blots at an earlier age than did boys. Individual cards differed widely in regard to their strongest connotations. Children significantly differentiated the majority of responses and determinants on the semantic scales for all age groups. The connotations of the cards, responses and determinants tended to be consistent with commonly held Rorschach interpretations. In general, the findings for children were consistent with the results previously reported for adults. The connotations of chromatic inkblots were found to differ significantly from those of achromatic blots for the third and ninth grades, but not for sixth grade children. Statistically significant clusters of meaning for three age groups of children were found to exist, based on the presence of movement determinants and on a combination of movement, shading and chromatic color. Only for the sixth and ninth grade girls did the semantic scales have a single hierarchy of importance for ordering or differentiating both inkblots and responses of determinants. A communality of connotative meaning between inkblots on the one hand, and responses and determinants commonly associated with the blots on the other, is found only for ninth grade children. Low intergroup agreement was found across grades in mean scale ranking for the inkblots, but high agreement in mean scale ranking of responses and determinants.     

Measuring Generalized Expectancies for Negative Mood Regulation: Initial Scale Development and Implications

A scale measuring generalized expectancies for negative mood regulation (NMR) was developed. The construct was defined as the expectancy that some behavior or cognition will alleviate a negative mood state. Data from five samples of college undergraduates (N = 1,630) were reported. Internal consistency, discriminant validity from social desirability, and temporal stability were demonstrated for a 30-item scale derived from an initial pool of 50 items. Further analyses revealed (a) modest correlations of the 30-item scale with internal-external control, (b) that high scorers on the NMR scale reported few symptoms of depression, and (c) that the NMR scale predicted a different pattern of emotions than the Beck Depression Inventory did. Discussion focused on possible roles for expectancies for negative mood regulation in the coping process and directions for future research on the mood regulation process.